Toners generally used widely heretofore are produced by dry-blending a styrene/acrylate-type co-polymer powder obtained by suspension polymerization with a coloring agent such as carbon black and optionally a charge controlling agent and/or a magnetic material, melt-kneading the mixture by an extruder or the like, and then pulverizing and classifying the kneaded mixture (see Japanese Laid-Open Patent Publication No. 23354/1976).
With the conventional toners obtained by the above melt-kneading/pulverizing method, controlling of the particle diameter of the toners is limited, and it is substantially difficult to produce toners having an average particle diameter of not more than 10 microns, especially not more than 8 microns, above all not more than 5 microns, in good yields. Moreover, it is difficult to avoid the defect that developers prepared from the toners have a low resolution and poor chargeability and fogging occurs.
It has also been proposed to produce a toner by copolymerizing monomers in the presence of a coloring agent. The product, however, still has the defect that it has insufficient chargeability and fogging occurs.